Well close-off means



NOV. 1966 E. E. WARRINGTON WELL CLOSEOFF MEANS Filed Sept. 5, 1963 2 Sheets-Sheet l 1966 E. E. WARRINGTON 3,

WELL CLOSE-OFF MEANS Filed Sept. 5, 1963 2 Sheets-Sheet .2

BY AL MW ATTORNEY United States Patent 3,283,323 WELL CLOSE-OFF MEANS Elbert E. Warrington, 9862 Meadowdale St, Baton Rouge, La. Filed Sept. 5, 1963, Ser. No. 306,7?9 15 Claims. (Cl. 166-182) This invention relates to improvements in well closeoif means and is more particularly directed to off-bottom well close-off means designed to be connected into a drilling string for closing off the hole when temporary shutting-in of the well is considered to be desirable or necessary, for example, when high pressure sands are encountered while drilling.

Stated broadly, a major object of the invention is the provision of effective bottom-hole or off-bottom means for closing off oil and .gas wells near the bot-om thereof when the drill bit operating on bottom encounters high pressure sands or other sub-surface and particularly bottom-hole pressure conditions likely to cause blowout and the hazards incident thereto such as damage to casing and drilling rig, and contamination if not serious loss of drilling mud.

A more particular object of the invention is the provision of bottom-hole close-off means as aforesaid which may be simply and readily placed in operation from the surface upon detection of a sub-surface pressure condition likely to adversely affect drilling, such as increase of volume or pressure of drilling mud in the system.

Yet another object or the invention is the provision of improved and simplified bottom-hole close otf means for oil and gas wells of a type and design enabling it to be connected into the tubular drill string (drill pipe) above the bottom hole assembly and which is moreover so con structed and arranged as to be readily operable from the surface to close off both the bore of the drill string and the annular space between the hole wall and the string at respective locations thereof closely adjacent the bit working on the hole bottom.

The above and other objects and features of advantage of a down-hole well close-off means according to the present invention will be hereinafter set forth in or become apparent from the following detailed description, in which reference is had to the accompanying drawings illustrating a typical physical embodiment hereof, in which:

FIG. 1 is an elevational view, in section, of downor bottom-hole well close-off means according to the invention shown to be connected in a drill string at a location assumed to be just above the bottom hole assembly which includes the drill bit, the view illustrating the parts of the close-off means in their normal inoperative positions and/or relationships;

FIG. 2 is a similar view but illustrating said parts in their respective well close-off or shutting-in positions;

FIG. 3 is a transverse section taken on line 33 of FIG. 1;

FIG. 4 is a fragmentary exploded view of the packer mandrel-sleeve members of the close-01f means, which further illustrates typical J-joint means effective therebetween;

FIGS. 5 and 6 are diagrammatic views illustrating the manner of operation of the respective upper and lower J-joints as aforesaid.

Referring to the drawings in greater detail, reference numeral 10 generally designates a downor bottom-hole well close-off means according to the invention considered as a complete assembly and which is shown,to be connected at its upper end to the lower end of the lowermost section of a drill string 12, usually made u of a plurality of such sections connected end-to-end by suitable joint means in the conventional manner, and at its lower end to the upper end of the bottom-hole assembly indicated at 14 and which conventionally mounts a drill point or hit (not shown) normally working on the bottom of the hole.

From its upper end downwardly, said well close-off means illustratively comprises the following: an upper tubular coupling section 26) connected at its upper end by mating threads to the lower end of the drill string 12 so as to depend downwardly in fixed axial relation therefrom; a coaxially and telescopically related tubular packer mandrel 24 depending from the upper coupling section and being drivingly and separably connected thereto by upper joint means generally designated J to be later described in detail; a sleeve 26 disposed in encircling re* lation about the lower end portion of the packer mandrel for the major portion of its length and depending a small distance downwardly therefrom and being drivingly and non-separably connected to said mandrel by lower joint means designated 1 also to be later described in detail; an external, radially outwardly distensible or inflatable sleeve-form upper packer 28 disposed about the middle length position of the packer mandrel in position to be acted upon, i.e. relaxed or slackened, by opposed external shoulders 28a, 28b on the mandrel 24 and encircling sleeve 26, respectively; and an internal, radially inwardly deformable sleeve-form lower packer 30 which normally defies a portion of the common bore extending through the mandrel 24 and the lower end of said sleeve and which is positioned so as to be axially compressed between a downwardly facing shoulder 30a defined by the lower end edge of the mandrel and an opposed, upwardly facing, lower level internal shoulder 30b formed in the bore of said sleeve 26.

Heavy coil springs S and S interposed respectively between a downwardly facing external shoulder 32a on the upper end of the coupling section 20 and the opposed upper-end edge 32b of the mandrel 24 and between opposed (external) mandrel and (internal) sleeve shoulders 34a, 3412 located within the axial length of the sleeve 26 are provided as shown. Said springs, which are effectively reactive between the drill string 12 (whose weight is normally supported from the surface) and the bottomhole assembly 14 including the drill bit, serve the plural functions of locking the J-joints J and 1 in their normal locked and drive transmitting positions, of biasing the drill bit against the bottom of the hole with light pressure which can be controlled from the surface, and of normally maintaining the packers 28 and 30 in the r respective non-distended and non-deformed COHClllIOIlS in which they are illustrated in FIG. 1, in which position the drilling mud is free to flow downwardly and unobstructedly through the bore of the herein well closeoff means or assembly lit and thence upwardly through the annular space between the wall of the hole and the axially related bottom-hole assembly.

At this point of the description it is explained that during normal drilling, the J-joints J and 1;; provide rotary drive connections first between the drill string 12 and the packer mandrel 24 via the coupling section 20 and thence between said packer mandrel and the bottom hole assembly 14- via the sleeve 26. More particularly, each of said J-joints preferably takes the form generally shown in FIG. 4, although it is to be understood that this view is diagrammatic only and does not reflect the exact configuration of the J-slots employed in said joints. Suffice it to say that each of the joints comprises an inwardly opening I-slot 40 and a driving key or lug 42 operating therein as will be explained in detail, the slot 40a of the upper joint (FIG. 5) being milled or otherwise provided in the upper end portion of the bore wall surface of the packer mandrel 24 into which the lower end of the coupling section 20 depends and its companion driving key 42a being formed on and projecting from the peripheral surface of said lower end, and the slot 40b of the lower joint 1 (FIG. 6) being milled or otherwised provided in the borewall surface of the upper end portion of the mandrel encircling sleeve 26 and its companion driving key 42b being formed on and projecting from the peripheral surface of the mandrel-length portion facing said slot 40b.

Referring to FIG. 5, the J-slot 40a of the upper joint 1 has a long vertical leg 44a of width slightly greater than that of the key lug 42a and which opens through the upper end edge of the packer mandrel 24 and connects at its lower end with a cross leg 46a whose vertical dimension slightly exceeds that of said key or lug, and a short vertical leg 48a having height and width substantially equaling the length and width of said key 42a and which extends upwardly from the end of the cross leg 46a opposite that into which the long leg 44a connects. Normally, the key 42a seats within the short leg 48a (as in FIG. wherein it is maintained by the bias of the upper spring S and thus in such position the key functions as a positive drive connection between the drill string 12 and mandrel 24 via the coupling section 20. It will be seen, however, that lowering of the drill string and coupling section will effect corresponding lowering of the driving key 42a to a neutral position within the slot cross-leg 46a, indicated in broken lines. Thereupon, limited rotation of the drill string 12 and attached coupling section 20 in counter-clockwise direction with respect to the mandrel 24 is possible, and upon so rotating the drill string the proper amount as to bring said driving key 42a into alignment with the long leg 44a of the slot, the drill string and upper coupling section may be physically raised from said mandrel and thereby separated from said mandrel. Conversely, the drill string and upper coupling section may be coupled to and drivingly connected to the mandrel 24 by lowering the former on to the mandrel in proper angular position with respect thereto as permits the driving key 4a to enter the open-top long leg 44a of the slot 40a, then rotating the drill string in clockwise direction the amount necessary to bring the driving key into alignment with the short leg 48a of the slot, and finally releasing the parts for relative separating movement under the bias of the spring S whereupon the driving key will reseat itself in said slot leg 48a.

Referring to FIG. 6, the slot 40b of the lower joint I is similarly formed with a long open-top vertical leg 44A, a cross leg 46]) and a short vertical leg 48b. The driving key or lug 42b is normally seated in driving position in the short leg 48b under the bias of the lower spring S but is lowerable to a neutral position indicated by broken lines. While in this neutral position, the driving key 42a may move relatively to the right with rotary motion of the mandrel 24 in counter-clockwise direction but it is not permitted to move to a position into alignment with the long vertical leg 44b of the J-slot 40b (as could result in vertical separation of mandrel 24 from sleeve 26) by means such as set screws 50 threaded inwardly through the wall of the sleeve 26 to extend well into the cross leg 46b of said slot adjacent the end thereof with which the long vertical leg 44b thereof connects, the set screws thus serving to bar entry of the key 42]; into the said slot leg 44b. However, the J configuration of the slot 40b serves the useful purpose of permitting initial entry of the key 42b thereinto.

According to the invention, the aforesaid lowering of the driving keys 42a, 42b from their driving to their socalled neutral position as described above is effected by setting the drill bit on bottom, that is, permitting the drill string to lower on to the bottom hole assembly against the resistance of the aforesaid springs S and S by an amount which by design is such that the springs compress approximately the vertical distance that said keys move in partaking of movement between their driving and neutral positions. Responsive to the drill bit being set on bottom as aforesaid, plural results are attained in addition to driving key movement as aforesaid. Firstly, the upper pressure packer 28 which normally is tautened is slackened and thereby conditioned for distension. Secondly, the lower or deformable packer 30 is compressed in axial direction between the aforesaid shoulders 30a, 30b and thereby deformed inwardly to a position in which it effectively closes the lower end of the bore extending through mandrel 24 and sleeve 26, thus preventing external pressure or contamination from entering the bore from its lower end and interrupting normal drilling mud flow. Finally, according to another feature of the invention, lowering of the mandrel 24 with respect to the sleeve results in the drilling mud from the bore flowing to the inner side of the distensible packer 28 under the pressure requisite to effect distension thereof and in the sealing off of the annular space between the close-off assembly 10 and the wall of the hole being drilled, thereby temporarily shutting-in the well.

The means by which lowering of mandrel relative to sleeve effects distension of the upper or pressure packer as aforesaid will now be described. Referring to FIGS. 1 and 2, there is provided adjacent the lower end of the packer mandrel 24, a port 54 connecting the bore and an annular space between the lower end of said mandrel and the lower end of the sleeve. Also communicating with said annular space is a port 56 connecting to the lower end of a longitudinal, upwardly extending passage 58 provided in a longitudinal rib 6011 which, if formed separate from the sleeve 26, is fixedly welded thereto, said passage connecting at its upper end to a port 62 in the upper end of said sleeve, in turn communicating with an annular space provided between said upper end and the packer mandrel 24 and which opens to the inner side of the packer 28.

In the normal axial position of the mandrel (FIG. 1), the port 54 is closed off from the port 56 and passage 58 by one or more of the plurality of O-rings 64 operating in said annular space between the lower end of the mandrel and said sleeve (and also in the annular space between the upper end of the mandrel and the lower end of the coupling section 20) and said passage 53 is normally maintained closed at both ends by lower and upper check valves 66a, 66b which are set to open only upon the occurrence of a predetermined pressure of drilling mud acting on their relatively bore sides. However, upon the mandrel 24 lowering with respect to the sleeve 26 as aforesaid, the port 54 is lowered a corresponding amount which by design is such as to establish full communication between the ports 54 and 56, whereupon drilling mud flows at said predetermined pressure (which is of course sutficient to effect full opening of the check valves 66a, 66b and distension of the packer 23) through the passage 58 and port 62 to the inner side of the packer 28, thereby effecting distension of the latter into pressure contact with the wall of the hole, as in FIG. 2. Accordingly, assuming deformation of the lower packer 34) to have already occurred, complete closing-off or shutting in of the well just above the bit resting on the bottom is achieved.

Means are also provided to effect deflation of the packer 28 following its distension as aforesaid when such is desired. Illustratively, such means comprises a port 70 in the upper end of the sleeve bore which interconnects the space to the inner side of the packer with the upper end of a longitudinal passage 72 provided in an external rib b, afiixed to or formed on the sleeve 26 diametrically opposite the aforesaid rib 60a, which passageway connects by way of a lower port 74 to the annular space between the lower ends of mandrel and sleeve, which in turn connects to the mandrel bore through a port 76, preferably disposed diametrically opposite the aforesaid bore port 56. Ball checks 78a, 78b prevent flow of mud through the passageway 72 during normal operation.

The operation of the oiT-bottom Well close-off means of the invention is as follows: Assuming that high pressure sands are encountered during normal drilling, and by high pressure is meant pressure suflicient to contaminate the drilling mud and/or increase its volume, or to cause sticking of the drill or blow-out and possible damage to casing and drill rig, etc., the mud pump is shut oil and the drill bit is set on the bottom by lowering of the drill string 12. As explained above, such causes axial compression and thereby radial inward deformation of the lower packer 3t) and thereby closing off of the lower end of the bore .to the high pressure sands, and it further brings the mandrel port 54 into registry with the port 56 of the sleeve which leads via passage 58 to the inner side of the upper packer 28, which latter has been slackened and thereby conditioned for radial expansion or distention by said lowering of the drill string. The mud pump is then placed in operation at a pressure sufficient to distend the upper packer in radial outward direction against the wall of the hole, thus also closing 01f the annular space normally surrounding the drill string and bottom hole assembly to the upward flow of the pressure sands.

The aforesaid lowering of the drill string relative to bottom hole assembly also resulted in lowering of the driving keys 42a, 42b of the J-joints J and 1 from their respective driving positions in their slots Mia, 40b. The drill string 12 and coupling section may now be disconnected and raised from the packer mandrel and sleeve secured by the set packer 28 as aforesaid, thus to by-pass drilling fluid to the annulus above the external packer 23, by turning the drill string in counter-clockwise direction the angular amount necessary to align the key 42a with the longer vertical leg 44a of the upper I-joint slot 4% and then lifting the drill string. Corresponding separation of the locking and driving key 4211 of the lower joint J from its slot 4% is not possible, however, because of the set screws Stl which block movement of the key 42b into alignment with the longer leg of the J slot 4% in which it operates, and thus there is no likelihood of the packer mandrel pulling away from the sleeve 26 of the bottom hole assembly 14 connected to the latter.

If it is desired to resume drilling, a mud pressure above the set close-off means may now be adjusted, by any of the conventional procedures for varying drilling fluid density, to that required to overcome the objectionable high pressure of the sands, thus in effect rendering said high pressure harmless. Of course, any other appropriate or additional means to overcome the high pressure of said sands may be resorted to, depending on the particular conditions encountered. But in any case, when such has been accomplished, the drill string may be re-lowered into and turned with respect to the still set mandrel in manner as to effect re-positioning of the locking and driving keys 42a, 42b in the short legs 48a, 48b of their respective joint slots 40a, 40b. Such re-positioning also effects relaxation of the lower packer 39 to its normal (FIG. 1) configuration and it further brings about release of the mud pressure from the inner side of the upper packer 28, whereupon the latter is free to resume and does so resume its deflated and tautened condition, in which it is shown also in FIG. 1, or, in the event that it is not desired to resume drilling immediately, the well close-off means of the invention may be employed as temporary well shutting-in means for the interval that drilling is stopped.

As many changes could be made in carrying out the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Iclaim:

1. Oil-bottom well close-off means adapted to be connected into the drill string above the bottom-hole assembly which mounts the drill bit for closing off the well when high pressure conditions likely to adversely aflect drilling are encountered while drilling comprising, in combination: an upper tubular coupling section connected at its upper end to the drill string proper; a coaxial tubular packer mandrel depending therefrom; a coaxial sleeve encircling the mandrel for a major portion of its length and depending a short distance downwardly from said mandrel; normally inactive, radially expandable packer means interposed between opposed shoulder means on the packer mandrel and sleeve, respectively; normally inactive, radially inwardly deformable bore close-off means normally defining a lower length portion of the bore through the mandrel and sleeve and interposed between opposed shoulder means on said lower ends of the mandrel and sleeve, respectively; joint means operatively connecting the mandrel to the coupling section and the sleeve to said mandrel; spring means normally exerting bias in downward direction on the mandrel with respect to the coupling section and on the sleeve with respect to the mandrel and establishing the normal axial working relation of said parts but being yieldable to permit lowering of the drill string with respect to said close off means and the bottom-hole assembly; normally closed passage means extending between the bore of the mandrel and the inner side of said first packer means for supplying drilling fluid from the bore to said packer means under the pressure required to eifect radial expansion thereof; said passage means including normally non-communicating port means in said mandrel and sleeve, respectively, disposed above said bore closs-off means; the construction and arrangement being such that lowering of the drill string as aforesaid effects deformation of said bore close-off means and establishes communication between said port means, thereby to close off the here from the well hole and to admit drilling fluid from the bore through said passage means to the inner side of the expandable packer means as causes same to expand into sealing engagement with the wall of the well hole.

2. Well close-off means according to claim 1, wherein said spring means comprises an upper external coil spring interposed between a downwardly facing external shoulder on the coupling section and the upper-end edge of the packer mandrel, and a lower coil spring contained within the sleeve and interposed between opposed shoulde-rs on the mandrel and sleeve respectively.

3. Well close-otf means according to claim 1, wherein said joint means comprise an upper separable driving joint between the upper coupling section and the packer mandrel and a lower non-separable driving joint between said packer mandrel and said sleeve.

4. Well closeoiT means as set forth in claim 3, wherein said upper joint includes means for locking the mandrel to the upper coupling section when the drill string is rotated in one direction and for unlocking the drill string from the mandrel when said drill string is rotated in the opposite direction.

5. Oti-bottom well close-off means comprising a tubular packer assembly connected into the drilling string above the bottom hole assembly mounting the drill bit, said packer assembly including external packer means for sealing off the annulus between said packer assembly and the hole wall and full opening internal bore closing-off means which normally provides a length portion of the bore through the packer means and having a norm-ally unobstructed bore of diameter substantially equal to the packer bore for closing off said packer bore, and means responsive to lowering of the drill string with respect to the bottom hole assembly for effecting setting of said external packer means and for actuating said bore closingofi means to its bore closing-off position.

6. OtT-bot-tom well close-off means according to claim 5, wherein combination joint and driving means interconnect the drill string and packer assembly and such means is operative to eflfect physical disconnection of the drill string from the packer assembly following setting of the packer means.

7. Off-bottom well closure means according to claim 5, wherein said bore closing-off means comprises a radially inwardly deformable sleeve-form member of a material and being so mounted as to deform inwardly to a boreclosing shape when compressed in axial direction.

8. Off-bottom Well close-off means according to claim including means for effecting by-pass of the drilling fluid from the drill string directly to the annulus above the external packer.

9. Off-bottom well close-off means according to claim 5, wherein said external packer means is radially extensible by pressure fluid effective on its inner side and wherein said well close-off means further includes normally inactive means for supplying pressure fluid to the inner side of said external packer means to effect radial extension thereof and means for activating said last means in response to lowering of the drill string as aforesaid.

11}. Off-bottom Well close-off means according to claim 9, wherein said pressure fluid comprises the drilling mud which normally flows downwardly through the bore.

11. A down hole well close-01f tool for inclusion in a drill string and for flowing drilling fluid therethrough during drilling operations, the tool comprising:

a first generally tubular member having an axial bore therethrough in communication with the bore of the drill string,

a second generally tubular member mounted inside the first tubular member for relative axial movement therewith within predetermined limits,

external packer means supported by at least one of the tubular members for sealing off the annulus between the well bore wall and the outside surface of the tool, the external packer means being radially outwardly expansible incident to predetermined movement impart-ed to the drill string, and

full opening internal bore closure means supported by one of the tubular members for closing off the axial bore of the tool upon actuation thereof, the bore closure means normally having an unobstructed bore extending longitudinally therethrough of diameter substantially equal to that of said tool bore and adapted for actuation to the closed position in response to relative axial movement between the first and second tubular members.

12. The apparatus as claimed in claim 11 including:

by-pass means for flowing drilling fluid down the drill string and out to the annulus at a point spaced above the external packer means and the bore closure means.

13. The apparatus as claimed in claim 11 including:

means provided in the first and second tubular members for transmitting therebetween rotational forces applied to the drill string.

14. The apparatus as claimed in claim 13 wherein:

the first tubular member is connected at one end to the drill string and the second tubular member is connected at the opposite end to the drill string, whereby tension, compression and rotation forces applied to the drill string are transmitted through the tool.

15. A down hole well close-off tool for inclusion in a drill string during drilling operations, the tool comprising:

a first generally tubular member having an axial bore therethrough in communication with the bore of the drill string,

a second generally tubular member mounted inside the first tubular member for relative axial movement therewith within predetermined limits,

external packer means supported by at least one of the tubular members for sealing off the annulus between the well bore wall and the outside surface of the tool, the packer means being radially outwardly expansible in response to pressurized fluid applied thereto,

conduit means passing through the wall of at least one of the tubular members for supplying pressurized fluid to the packer means, the conduit means being operative in response to relative axial movement imparted to the first and second tubular members, and

full opening internal bore closure means supported by one of the tubular members for closing off the axial bore of the tool upon actuation thereof, the bore closure means normally having an unobstructed axial bore therethrough of diameter substantially equal to that of said tool bore and adapted for actuation to the closed position incident to predetermined movement imparted to the drill string.

References Cited by the Examiner UNITED STATES PATENTS 1,706,072 3/1929 Rieger -321 X 1,827,842 10/1931 Getty 166182 1,924,425 8/1933 Wickersham et al. 166-187 X 2,042,817 6/1936 Wilcox 166-196 X 2,290,141 7/1942 Burt 166-201 X 2,497,185 2/1950 Reistle 166-487 2,510,300 6/1950 Walls 17565 2,832,566 4/1958 Bielstein 17565 2,783,026 2/1957 Reistle 175325 X FOREIGN PATENTS 222,794 10/ 1924 Great Britain.

JACOB L. NACKENOFF, Primary Examiner.

CHARLES E. OCONNELL, Examiner.

0 I. A. CALVERT, D. H. BROWN, Assistant Examiners. 

5. OFF-BOTTOM WELL CLOSE-OFF MEANS COMPRISING A TUBULAR PACKER ASSEMBLY CONNECTED INTO THE DRILLING STRING ABOVE THE BOTTOM HOLE ASSEMBLY MOUNTING THE DRILL BIT, SAID PACKER ASSEMBLY INCLUDING EXTERNAL PACKER MEANS FOR SEALING OFF THE ANNULUS BETWEEN SAID PACKER ASSEMBLY AND THE HOLE WALL AND FULL OPENING INTERNAL BORE CLOSING-OFF MEANS WHICH NORMALLY PROVIDES A LENGTH PORTION OF THE BORE THROUGH THE PACKER MEANS AND HAVING A NORMALLY UNOBSTRUCTED BORE OF DIAMETER SUBSTANTIALLY EQUAL TO THE PACKER BORE FOR CLOSING OFF SAID PACKER BORE, AND MEANS RESPONSIVE TO LOWERING OF THE DRILL STRING WITH RESPECT TO 